The present invention relates to a tandem type trochoid pump employing two sets of trochoid pumps and a method of assembling the tandem type trochoid pump.
Japanese Published Utility Model No. 3-5990 has proposed a tandem type trochoid pump which is arranged to drive two trochoid pumps by applying a rotational force to a drive shaft of the pump. The two trochoid pumps are set such that a timing of communicating an operation chamber and a discharge port of one pump is differentiated from a timing of the other pump, in order to decrease a pulse pressure of the oil pump.
Since two inner rotors of the two pumps are arranged so as to integrally rotate with the drive shaft, it is difficult to respectively install the two inner rotors having different phases into corresponding outer rotors. In order to solve this difficulty, Japanese Published Utility Model No. 3-5990 has employed an intermediate casing for sub-assembling one of the two pumps to improve a workability during assembly process.